1. Field of the Invention
The present invention relates to compositions utilized for the treatment of styes and related inflammations of the eyelid area.
2. Description of the Prior Art
A sty, technically known as a hordeolum, is a furuncular inflammation of the connective tissue of the eyelid near a hair follicle. Styes are generally caused by bacterial infections of the sebaceous or marginal glands of the eyelid and are one type of blepharitic infection, i.e. infections causing inflammation of the eyelids. Styes and other blepharitic infections are generally responsive to topical antibacterial agents, and a variety of such agents have been incorporated into topical preparations to be applied to the eyelid for the treatment of such infections.
Among the preparations commonly used for the treatment of styes and other infections of a similar nature, are ointments containing, for example, a carrier such as petrolatum, mineral oil or lanolin, an astringent such as zinc sulfate, and a bactericidal agent, frequently a mercury salt such as mercuric iodide or mercuric oxide. One representative commercially available sty ointment contains about 1% yellow mercuric oxide in an ointment base consisting primarily of petrolatum and mineral oil.
Many of the prior art sty ointments as well as other topical germicidal ointments also contain a small quantity (on the order of a few percent by weight) of boric acid, which serves to stabilize the mercuric oxide against color/chemical deterioration. Examples of the use of boric acid and related compounds as stabilizers in antiseptic ointments are disclosed in U.S. Pat. Nos. 1,493,564 and 372,852.
Although the mercuric oxide or other mercury-compound containing petrolatum-type ointments have been effective in the absence of boric acid for the treatment of styes and related blepharitic infections, these preparations have shelf lives of less than about six months because the mercuric oxide active ingredient thereafter tends to decompose and discolor, turning a dark brown shade. This gives the prior art ointments an aesthetically displeasing appearance and discourage patient use of the same, making it commercially undesirable. Such discouragement is particularly detrimental in view of the fact that most mercuric oxide-containing sty ointments are marketed over the counter and do not require a physician's prescription; hence, the consumer is completely free to choose which ointment to use if any, and an ointment which discolors within a few months after manufacture is not attractive to the consuming public, even if medically effective.
Another drawback of prior art sty ointments, even those containing boric acid as a stabilizer, is that the preparations experience a reduction in their germicidal potency, and hence, their therapeutic efficacy, after about six months, particularly once the ointment containers have been opened. Moreover, no prior art sty ointment contains an ingredient or ingredients to enchance the bactericidal potency of the preparation and thus delay the time when the level of its therapeutic efficacy becomes unacceptable. To the present date, no preparation effective for the treatment of styes and similar infections of the eyelid has been developed which has a shelf life of more than about six months, both from the point of view of maintaining its original color and aesthetic appearance and from the point of view of substantially maintaining its germicidal potency, and yet contains only ingredients safe enough for use in an over the counter preparation purchased by self-medicating consumers.